Astronomy & Astrophysics

All Figures

$\begin{figure} \par\includegraphics[width=7.5cm,clip]{0403f1.eps} \end{figure}$ Figure 1: Prescribed heating rate for different values of the damping length: H_m = 2 Mm (dotted), H_m = 3 Mm (solid), H_m = 5 Mm (dashed), and H_m = 6 Mm (dash-dotted), and H_m = 12.5 Mm (long dashes, heating function for static initial model). The total heat input into the loop is the same for all cases.
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In the text

$\begin{figure} \par\includegraphics[width=7.1cm,clip]{0403f2.eps} \end{figure}$ Figure 2: Temperature along the coronal loop. Initial state (solid line, H_m = 12.5 Mm) and stable solution for H_m = 6 Mm (dotted line).
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In the text

$\begin{figure} \par\includegraphics[width=8cm,clip]{0403f3.eps} \end{figure}$ Figure 3: Evolution of mean temperature, $\langle T \rangle$ , as a function of time, for four different damping lengths of the heating function: H_m = 2 Mm (dotted), H_m = 3 Mm (solid), H_m = 5 Mm (dashed), H_m = 6 Mm (dash-dotted). Cf. Sect. 4.1. For comparison, the long-dashed line shows $\langle T \rangle (t)$ for a loop model where the heating is switched off at t=0.
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In the text

$\begin{figure} \par\includegraphics[height=23.3cm,width=14.8cm,clip]{0403f4.eps} \end{figure}$ Figure 4: Evolution of the temperature along the loop, T (z,t), for three different damping lengths of the heating function: H_m = 5 Mm (left), H_m = 3 Mm (center), H_m = 2 Mm (right). The loop footpoints are at z= 0 and 100 Mm, the apex is at z= 50 Mm.
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In the text

$\begin{figure} \par\includegraphics[width=6.5cm,clip]{0403f5.eps} \end{figure}$ Figure 5: Mean temperature, $\langle T \rangle$ , of the loop, as a function of mean pressure, $\langle p \rangle$ , for a loop of total length L = 100 Mm. Dotted: H_m = 2 Mm, solid: H_m = 3 Mm, dash-dotted: H_m = 6 Mm.
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In the text

$\begin{figure} \par\includegraphics[width=11.8cm,clip]{0403f6_corrected.eps} \end{figure}$ Figure 6: Formation of two simultaneous, lateral condensation regions for H_m = 3 Mm. Left panels, as functions of loop length: loop temperature (top), total radiative losses (middle), electron density (bottom). Right panels, as functions of loop temperature: radiative loss function (top), total radiative losses (middle), electron density (bottom). The following timesteps are plotted: $t=30~000~{\rm s}$ (solid), $t=31~000~{\rm s}$ (dotted), $t=32~000~{\rm s}$ (dashed), $t=33~000~{\rm s}$ (dash-dotted), $t=34~000~{\rm s}$ (dash-dot-dotted). The right panels display only data of the central part of the loop, between the two vertical lines shown in the upper left panel, for the first 4 timesteps. In some cases (dashed and dash-dotted curves in the middle and lower right panels) two branches are seen because of a slightly different evolution of the two loop legs.
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In the text

$\begin{figure} \par\includegraphics[width=12.1cm,clip]{0403f7_corrected.eps} \end{figure}$ Figure 7: Formation of a central condensation region for H_m = 5 Mm. Left panels, as functions of loop length: loop temperature (top), total radiative losses (middle), electron density (bottom). Right panels, as functions of loop temperature: radiative loss function (top), total radiative losses (middle), electron density (bottom). The following timesteps are plotted: $t=20~000~{\rm s}$ (solid), $t=22~000~{\rm s}$ (dotted), $t=24~000~{\rm s}$ (dashed), $t=26~000~{\rm s}$ (dash-dotted), $t=28~000~{\rm s}$ (dash-dot-dotted), $t=30~000~{\rm s}$ (long dashes). The right panels display only data of the central part of the loop, between the two vertical lines shown in the upper left panel, for the first 5 timesteps.
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In the text

$\begin{figure} \par\includegraphics[width=8.45cm,clip]{0403f8.eps} \end{figure}$ Figure 8: Formation of a shock front for H_m = 3 Mm. Gravitational acceleration, $g_\Vert (z)$ (dotted), and acceleration due to the pressure gradient, $\nabla p (z)/\rho (z)$ (solid) for t = 32 000 s (top row) and t = 34 400 s (bottom row). In the lower right plot, the free-fall velocity profile is indicated by a dashed line.
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In the text

$\begin{figure} \par\includegraphics[width=7.3cm,clip]{0403f9.eps} \end{figure}$ Figure 9: Comparison between the velocity profile for H_m = 5 Mm at t = 31 200 s (solid line) with the free-fall velocity from the loop apex at 50 Mm to the right footpoint at 100 Mm (dashed) and the local sound speed at t = 31 200 s (dotted line).
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In the text

$\begin{figure} \par\includegraphics[width=7.5cm,clip]{0403f10.eps} \end{figure}$ Figure 10: Velocity (top) and acceleration (bottom) of the condensation region for H_m = 5 Mm. The blob is accelerated by gravity and then slowed down by the pressure of the compressed transition region plasma underneath. The dashed line in the lower panel shows the effective gravitational acceleration, $g_\Vert$ , at the respective position of the blob.
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In the text

$\begin{figure} \par\includegraphics[width=7.6cm,clip]{0403f11.eps} \end{figure}$ Figure 11: Variation of total intensity (top) and mean Doppler shift (bottom) due to the falling condensation region, integrated over the right half of H_m = 5 Mm loop. The solid line displays C IV (154.8 nm), the dashed line O V (63.0 nm).
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In the text

$\begin{figure} \par\includegraphics[width=8.3cm,clip]{0403f12.eps} \end{figure}$ Figure 12: Line profiles of C IV (154.8 nm) and O V (63.0 nm) during the fall of the condensation region (H_m = 5 Mm) as seen from above. The flow towards the solar surface results in a redshift of around 10 km s^-1 and the emission stops abruptly when the condensation region drains through the footpoint.
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In the text

$\begin{figure} \par\includegraphics[width=13cm,clip]{0403f13a.eps}\vspace*{3mm} \includegraphics[width=13cm,clip]{0403f13b.eps} \end{figure}$ Figure 13: Formation of two condensation regions in a coronal loop for H_m = 2 Mm. The upper left plot shows the evolution of temperature along the loop, the upper right plot shows the corresponding velocities. The lower left plot displays the emission in C IV (154.8 nm), the lower right plot the emission in O V (63.0 nm.)
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In the text

$\begin{figure} \par\includegraphics[width=7.4cm,clip]{0403f14.eps} \end{figure}$ Figure 14: Relative intensity, $I_{H_m = 5~{\rm Mm}} / I_{H_m = 6~{\rm Mm}}$ , in C IV (154.8 nm) at the left (upper panel) and right (lower panel) footpoints.
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In the text

$\begin{figure} \par\includegraphics[width=8.15cm,clip]{0403f15.eps} \end{figure}$ Figure 15: Evolution of mean temperature, $\langle T \rangle (t)$ , using an increased mechanical energy flux of $F_{m0} = c \cdot 10^4$ W/m², for four different damping lengths of the heating function: H_m = 2 Mm (dotted), H_m = 3 Mm (solid), H_m = 5 Mm (dashed), H_m = 6 Mm (dash-dotted).
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In the text

$\begin{figure} \par\includegraphics[width=7.5cm,clip]{0403f1.eps} \end{figure}$	Figure 1: Prescribed heating rate for different values of the damping length: H_m = 2 Mm (dotted), H_m = 3 Mm (solid), H_m = 5 Mm (dashed), and H_m = 6 Mm (dash-dotted), and H_m = 12.5 Mm (long dashes, heating function for static initial model). The total heat input into the loop is the same for all cases.
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$\begin{figure} \par\includegraphics[width=7.1cm,clip]{0403f2.eps} \end{figure}$	Figure 2: Temperature along the coronal loop. Initial state (solid line, H_m = 12.5 Mm) and stable solution for H_m = 6 Mm (dotted line).
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$\begin{figure} \par\includegraphics[width=8cm,clip]{0403f3.eps} \end{figure}$	Figure 3: Evolution of mean temperature, $\langle T \rangle$ , as a function of time, for four different damping lengths of the heating function: H_m = 2 Mm (dotted), H_m = 3 Mm (solid), H_m = 5 Mm (dashed), H_m = 6 Mm (dash-dotted). Cf. Sect. 4.1. For comparison, the long-dashed line shows $\langle T \rangle (t)$ for a loop model where the heating is switched off at t=0.
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$\begin{figure} \par\includegraphics[height=23.3cm,width=14.8cm,clip]{0403f4.eps} \end{figure}$	Figure 4: Evolution of the temperature along the loop, T (z,t), for three different damping lengths of the heating function: H_m = 5 Mm (left), H_m = 3 Mm (center), H_m = 2 Mm (right). The loop footpoints are at z= 0 and 100 Mm, the apex is at z= 50 Mm.
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$\begin{figure} \par\includegraphics[width=6.5cm,clip]{0403f5.eps} \end{figure}$	Figure 5: Mean temperature, $\langle T \rangle$ , of the loop, as a function of mean pressure, $\langle p \rangle$ , for a loop of total length L = 100 Mm. Dotted: H_m = 2 Mm, solid: H_m = 3 Mm, dash-dotted: H_m = 6 Mm.
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$\begin{figure} \par\includegraphics[width=8.45cm,clip]{0403f8.eps} \end{figure}$	Figure 8: Formation of a shock front for H_m = 3 Mm. Gravitational acceleration, $g_\Vert (z)$ (dotted), and acceleration due to the pressure gradient, $\nabla p (z)/\rho (z)$ (solid) for t = 32 000 s (top row) and t = 34 400 s (bottom row). In the lower right plot, the free-fall velocity profile is indicated by a dashed line.
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$\begin{figure} \par\includegraphics[width=7.3cm,clip]{0403f9.eps} \end{figure}$	Figure 9: Comparison between the velocity profile for H_m = 5 Mm at t = 31 200 s (solid line) with the free-fall velocity from the loop apex at 50 Mm to the right footpoint at 100 Mm (dashed) and the local sound speed at t = 31 200 s (dotted line).
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$\begin{figure} \par\includegraphics[width=7.5cm,clip]{0403f10.eps} \end{figure}$	Figure 10: Velocity (top) and acceleration (bottom) of the condensation region for H_m = 5 Mm. The blob is accelerated by gravity and then slowed down by the pressure of the compressed transition region plasma underneath. The dashed line in the lower panel shows the effective gravitational acceleration, $g_\Vert$ , at the respective position of the blob.
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$\begin{figure} \par\includegraphics[width=7.6cm,clip]{0403f11.eps} \end{figure}$	Figure 11: Variation of total intensity (top) and mean Doppler shift (bottom) due to the falling condensation region, integrated over the right half of H_m = 5 Mm loop. The solid line displays C IV (154.8 nm), the dashed line O V (63.0 nm).
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$\begin{figure} \par\includegraphics[width=8.3cm,clip]{0403f12.eps} \end{figure}$	Figure 12: Line profiles of C IV (154.8 nm) and O V (63.0 nm) during the fall of the condensation region (H_m = 5 Mm) as seen from above. The flow towards the solar surface results in a redshift of around 10 km s^-1 and the emission stops abruptly when the condensation region drains through the footpoint.
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$\begin{figure} \par\includegraphics[width=13cm,clip]{0403f13a.eps}\vspace*{3mm} \includegraphics[width=13cm,clip]{0403f13b.eps} \end{figure}$	Figure 13: Formation of two condensation regions in a coronal loop for H_m = 2 Mm. The upper left plot shows the evolution of temperature along the loop, the upper right plot shows the corresponding velocities. The lower left plot displays the emission in C IV (154.8 nm), the lower right plot the emission in O V (63.0 nm.)
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$\begin{figure} \par\includegraphics[width=7.4cm,clip]{0403f14.eps} \end{figure}$	Figure 14: Relative intensity, $I_{H_m = 5~{\rm Mm}} / I_{H_m = 6~{\rm Mm}}$ , in C IV (154.8 nm) at the left (upper panel) and right (lower panel) footpoints.
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$\begin{figure} \par\includegraphics[width=8.15cm,clip]{0403f15.eps} \end{figure}$	Figure 15: Evolution of mean temperature, $\langle T \rangle (t)$ , using an increased mechanical energy flux of $F_{m0} = c \cdot 10^4$ W/m², for four different damping lengths of the heating function: H_m = 2 Mm (dotted), H_m = 3 Mm (solid), H_m = 5 Mm (dashed), H_m = 6 Mm (dash-dotted).
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